O-Ring Materials - EP, EPR, EPDM

There are two types of ethylene-propylene rubber:
1. EPR: saturated (inert) copolymer of ethylene and propylene.
2. EPDM: It is a copolymer of ethylene and propylene, or a terpolymer of ethylene and propylene with a small amount of a third monomer (usually a diene). EPDM has relatively active chemical properties and can be vulcanized. This copolymer must be treated with hydrogen peroxide.

Material properties:
● Excellent resistance to ozone, sunlight and weathering.
● Very good elasticity at low temperatures.
● Good chemical resistance (many dilute acids and bases, polar solvents).
● Good electrical insulation properties.

Applicable industries:
● Sealing rings, automobile sealing strips, building sealing strips, dust jackets, wires and cables, braking systems, drinking water systems and other weather-resistant products.

Best●   Better○    Good△   BadX

Rubber type
(ASTM Abbreviation )		Ethylene Propylene Rubber
EP, EPR, EPDM
Chemical structureEthylene and propylene copolymer 
(terpolymer)
Main featureAnti-aging, ozone resistance, weather resistance, chemical resistance, abrasion resistance, water resistance, alcohol resistance and ketones, not for food use or exposure to aromatic hydrogen.
Pure rubber propertiesproportion
Muni viscosity ML1+ (100℃)		0.86 ∼ 0.87
50 ∼ 150
Physical properties of synthetic rubberPossible JIS hardness range
General temperature range(℃) 
Special temperature range(℃)
Tensile strength (kg/cm2)
Elongation (%)
Anti-elastic
Cracking
Wear resistance
Bending resistance		40 ∼ 90
-40 ∼ 130
-50 ∼ 150
50 ∼ 200
800 ∼ 100
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Various properties of synthetic rubberlubricating oilEngine oil
Gear Oil
Motor oil
Shaft lubricant
Refrigeration oil
Butter
Lithium oil
Oyster sauce		X
X
X
X
X
X
X
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Working oilPot shaft oil
Oil + Water emulsion system
Water + Glycol
Phosphate ester
Si
Brake Fluid
Gear oil		X
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X
Fuel oilLight oil、kerosene
Heavy oil
Gasoline		X
X
X
WaterWater、Warm water
Water vapor、Hot water
Antifreeze water
Water cutting oil		●
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Drug

Hydrochloric acid 20%
Sulfuric acid 30%
Nitric acid 10%
Caustic soda 30%
Benzene
Trichloroethylene
Alcohol
Vinyl glycerol
Liquid fat
Alcohol
Ether
Ketone (MEK)
Acetic acid、Ethyl ester

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X
X
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X
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GasLPG
Urban gas
Ozone
Freon 12
Freon 22		X
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Other

Food Sanitation Law
Vacuum、Atmosphere 10mm kg 
10-4 ~ 10-9

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The main purposeWire covering, automotive windshield, window frame, water vapor radiator.